I hope that they're just getting the attention of everyone not already interested in the Hitman games, and will follow up with more in depth videos showcasing different ways of playing. You've always been able to go in guns blazing (although earlier it's not exactly been the best approach) like you've always been able to sneak inside undetected.
If they still keep the sneaking while improving the guns approach, everybody wins!

Like the new Deus Ex, everybody was all up in arms about everything getting dumbed down, until someone played the leaked press game (which was a quarter of the full game or something?) and basically said that it was very good and still true to the core game, despite all the differences.

I'm not afraid of change, and honestly I think they're right in the franchise needing a tune-up. And it sounds like they know and acknowledge their biggest fans wanting to keep things hard and not having their hands held, and so far it seems like they're working towards making it both more accessible for newcomers and still challenging to the hardcore fans.

When people first heard it would have a cover system they immediately thought that it would make it like Gears of War, without thinking that it also could make stealth way more engaging.

They stated in the interview that there will be both huge levels that you could take your time with, and smaller levels in which you would need to/be able to take a more hands-on approach. They felt they needed some better pacing and to keep things more interesting, and as long as the smaller sequences doesn't detract from the game time with the larger levels, I don't see who can complain.

I just found an interesting interview video here in which they discuss game mechanics and stuff. And where the dude from IO says that the game will actually be more hardcore in certain areas (whatever that means) and that the replayability would be "extremely high" which I hope answers the creative ways of killing question.

This post got long! Man, I've got a special place in my heart for Hitman and if it turns out to be Kane & Hitman: Conviction I will personally take a crap on their doormat (they're within walking distance from here)